code: def test_grab_plugin_load():
      imageio.plugins.grab.BaseGrabFormat._ImageGrab = FakeImageGrab
      imageio.plugins.grab.BaseGrabFormat._pillow_imported = True
      _plat = sys.platform
      sys.platform = "win32"
  
      try:
          reader = iio.get_reader("<screen>")
          assert reader.format.name == "SCREENGRAB"
  
          reader = iio.get_reader("<clipboard>")
          assert reader.format.name == "CLIPBOARDGRAB"
  
          with raises(ValueError):
              iio.get_writer("<clipboard>")
          with raises(ValueError):
              iio.get_writer("<screen>")
  
      finally:
          sys.platform = _plat
          imageio.plugins.grab.BaseGrabFormat._ImageGrab = None
          imageio.plugins.grab.BaseGrabFormat._pillow_imported = False
  
file_path: imageio/tests/test_grab.py
imports: import sys
  import numpy
  from pytest import raises
  import imageio.v2
  import imageio.plugins.grab
label_desc: Use image node_id 1 for calling a global function with example usage: test_grab_plugin_load() without return types